The piezoelectric effect has two main types: direct piezoelectric effect and converse piezoelectric effect. When the piezoelectric components are affected by an electrical field, the electric dipoles will be extended through the direction of the electrical field. As a result, mechanical energy is transformed from electric energy; this is so called direct piezoelectric effect. On the contrary, when applying mechanical stress/force to piezoelectric components, its electric dipoles will be shorten. Because the piezoelectric components resist this trend, they would generate voltage to keep the balance; this is therefore called converse piezoelectric effect.

We often hear the phrase “sound wave” in our daily life, but we do not really understand its meaning. Actually, every vibrating component is a source of sound, and it is presented in different forms. “Sound wave” is mechanical vibration of elasticity medium. Human can hear the vibration frequency of sound wave between 20Hz per second to 18,000Hz per second; this is called infrasound. If the vibration frequency is above 20,000Hz, it is called ultrasound. Ultrasound means the sound wave that human cannot hear. The hearing for ordinary human is between 16 KHz to 20KHz. Sound wave below 16 KHz called infrasonic wave and called ultrasonic wave if above 20 KHz.

The ultrasonic diffuser employs the principle of electron vibration and uses piezoelectric transducer to generate high frequency vibration (ultrasonic wave). The ultrasonic vibration breaks the water molecules to micro molecules, and the micro molecules are dispensed by fans.

The principle of PZT tactile feedback actuator in touchscreens is that when users touch the screen, a signal is sent to the touchscreen controller. The controller provides data about the precise screen location where the contact was made. This location data is sent to an embedded application that commands the touchscreen controller to perform a specified tactile effect.

The advantages are:：
       1. Errors are reduced due to the tactile feedback enhancement
       2. Efficiently improve the input speed
       3. Enhance customer satisfaction and increase safety

The PZT actuator actuates the speculum to reflect the laser in x-axis direction; therefore, a line is seen because of the visual staying phenomenon. If the PZT actuator moves in x and y direction, a circular graphic is seen due to the visual staying phenomenon.

You can find the Bowl Diffuser, Pulse Micro Diffuser, and Puff Whaley Diffuser in department stores and essential oil stores

All diffusers are made in Taiwan.

Yes, Sunnytec provides reliable after-sales and warranty as listed below:
Bowl Diffuser: One-year limited warranty, free repair if not man-made damage. If the warranty is expired, after-sales service is still available and the repair will be priced separately.
CI Diffuser: One-year limited warranty, free repair if not man-made damage. If the warranty is expired, after-sales service is still available and the repair will be priced separately.
Pulse Micro Diffuser: One-month limited warranty. Free replacement if not man-made damage.
Puff Whaley Diffuser: One-month limited warranty. Free replacement if not man-made damage

To avoid leading wires come off, please do not apply any pulling force that is more than 500g during the assembly.

We would call it a noise when the sound made by buzzer is not crisp and monotone. There are two possibilities：

1. Misuse：
     1.1 Driving voltage is too high: The excessive driving voltage causes the buzzer taps on other interior components, and the noise is resulted from the tapping sound.
     1.2  Incorrect driving frequency: The frequency is not properly set at the required frequency. For example, the required frequency is 2730Hz, but users set the frequency at 2400Hz. This incorrect frequency would easily cause noises; the noise is especially made when the frequency is set at 10% less than the requirement.rement.
2. Inferior quality：
    2.1 Buzzer plate is deformed：The plate for electromagnetic buzzer is being “placed” on the holder, not attached. Therefore, once there is an extreme force from outside, the plate will be moved from its original position and make noise.
     2.2 Foreign matter invasion：If powdered iron and/or iron filings get into buzzer during the assembly, it will also cause the noises.

 PZT buzzer uses the piezoelectric effect of the piezoelectric ceramic to actuate the metal plate which produces the vibration and sound. Whereas, the electromagnetic buzzer uses the electromagnetic effect to generate the sound: when electrifying, the vibration plate is being attracted, and the vibration plate is plucked back when there is no electricity. Therefore, PZT buzzer is driven by square wave, and electromagnetic buzzer is driving by 1/2 of square wave. PZT buzzer needs more voltage to generate sufficient sound pressure, above 9V is recommended. Electromagnetic buzzer needs only 1.5V to generate sound pressure above 85dB, but the current consumption is much greater than PZT buzzer. Under the condition of same size, the response frequency of electromagnetic buzzer could be lower. In general, the sound pressure of electromagnetic buzzer is no more than 90dB. In the case of PZT buzzer, it is easy to reach 100dB with a larger size, and reaching 120dB is also possible with different specifications.

Based on different driving signals, buzzer is sorted into two types: Self Drive and external drive. Even though there are other ways to categorize, they are still based on these two principles. For example, with (without) circuit board, DC or AC type, and with (without) power. Self Drive buzzer has the driving circuit board included. Therefore, only need to provide DC voltage, the attached driving circuit board will generate the pre-design frequency and voltage to the buzzer producing sound. As a result, the frequency of Self Drive buzzer is fixed.

There are three ways to install the buzzer plate into CASE: 1) Node; 2) edge; and 3) central. Referring to the graph above to determine the resonant frequency (fo) of the three installation methods.

Backup sensor employs the ultrasonic range finding principle to avoid car accidents. Through the ultrasonic wave generated by the backup sensor transducers installed at the back of the car - the wave would bounce back when hitting an object, the distance between the back of car and the object is calculated based on the time differences between transmitting and receiving signals .

1. When backing a car at a blind zone.
2. When backing a car, an object (children, cars, animals, and etc.) suddenly comes across.
3. When a parking space is too narrow to back a car.
4. When backing a car in dark such as at night and underground parking lot.